Paper filter of selective removal of a cigarette smoke vapor



United States Patent 3,403,689 PAPER FILTER 0F SELECTIVE REMOVAL OF A CIGARETTE SMOKE VAPOR Bobby J. Snblett and Cephas Hiram Sloan, Kingsport,

Tenn., assignors to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey No Drawing. Continuation-impart of application Ser. No. 425,920, Jan. 15, 1965. This application June 7, 1965, Ser. No. 462,050

3 Claims. (Cl. 131265) ABSTRACT OF THE DISCLOSURE A paper adapted for use in tobacco smoke filter elements capable of removing a substantial amount of hydrogen cyanide from tobacco smoke, the filter element containing deposited substantially uniformly throughout said paper a water soluble inorganic weak basic salt selected from the group of salts consisting of sodium phosphite, potasium phosphite and lithium phosphite.

This is a continuation-in-part of Serial No. 425,920 filed January 15, 1965.

This invention relates to filters that will remove hydrogen cyanide from smoke. More particularly it relates to paper filter elements containing additives which will effectively remove the hydrogen cyanide normally encountered in tobacco smoke.

In US. Patent 2,940,456 our co-worker Touey disclosed use of calcium and magnesium carbonates to remove particulate matter commonly referred to as tars. Since issuance of said patent a need has developed for removal from tobacco smoke of certain other substances not removable by said carbon-ates. Such substances include hydrogen cyanide. After extended investigation we have found a group of additives that will remove hydrogen cyanide from tobacco smoke when applied to paper used in tobacco smoke filters.

One object of this invention is to provide a paper filter element that will remove a considerable amount of hydrogen cyanide from the vapor portion of tobacco smoke. Another object is to provide a method of increasing the filtration efiiciency of paper tobacco smoke filter elements. Further objects will appear hereinafter.

In its broader aspects our invention involves applying to paper adapted for use in tobacco smoke filters a watersoluble inorganic salt of a Group Ia element. Preferred salts are sodium phosphite, potassium phosphite, lithium phosphite, sodium carbonate, potassium carbonate and lithium carbonate. The salts are preferably finely divided. The preferred particle size is such that the particles will pass through a lOO-mesh screen (US. Standard Sieve). The water-soluble inorganic salt may be applied by sitting, dusting, shaking, or from a water solution or dispersion. It may also be applied by spraying or rolling on the tow. More than one salt may be used as a mixture if desired.

The paper to which the salt additives may be applied according to our invention is any paper suitable for making tobacco smoke filters.

The water-soluble inorganic salt may be applied to the paper in the amount of from 1 to 30% by Weight, the preferred amount being 2 to by weight of the filter element prepared from the paper. By uniform application to the surface of the paper the salt is enabled to take advantage of the large surface area which provides the contact necessary for hydrogen cyanide removal.

According to one embodiment of our invention the paper is spread out to a width of 10-20 inches or so and sprayed with a water solution of the additive until 10 to 30% of the additive has been applied to the paper. The

paper is then dried, compacted and wrapped, for example, with a paper tape, to form a rod. It may be cut into any desired length and used either alone as a filter or in combination with other filters to make a dual or multiple filter.

The following examples are illustrative of our invention.

EXAMPLE I A 170-mm. length of cigarete filter paper weighing approximately 1 gram was spread out to a width of 15 inches and sprayed with a saturated solution of sodium ortho phosphite. The paper was allowed to dry and then reweighed. The paper containing the phosphite salt weighed 1.1 grams. The paper was then recompacted, wrapped with a paper tape to form a filter rod. The rod was cut into 17-m-m. segments which contained approximately 10 mg. of the phosphite salt. The 17-min. filter segments were attached to king-size cigarettes by means of a cellophane tape. The cigarettes were smoked with an automatic smoking device and the vapors which passed through the filter were collected and analyzed by spectrophotometry. The amount of hydrogen cyanide found was 50 pg. The amount of hydrogen cyanide found by analyzing a king-size cigarette with a similar paper filter, which was not treated with sodium phosphite, was 138 pg.

EXAMPLE II A paper napkin was moistened with a 30% potassium ortho phosphite solution and then dried. The dry napkin increased in weight by 15%. The napkin was compacted and wrapped with a paper tape to form a filter rod. The rod was out into 20-mm. segments and the segments attached to king-size cigarettes. The cigarettes were smoked on an automatic smoking device, and the vapors which passed through the filter were collected and analyzed for hydrogen cyanide by a spectrophotometric method. The vapors from a nonfilte'red king-size cigarette were collected, analyzed in the same manner, and the two analyses were compared. The nonfiltered cigarette delivered 151 jlg. of hydrogen cyanide; the cigarette containing the paper filter treated with potassium phosphite delivered only ,wg. of hydrogen cyanide.

From the preceding description and examples it may be seen that we have provided a paper filter element containing a water-soluble inorganic salt for improving cyanide removal.

We claim:

1. A paper adapted for use in tobacco smoke filter elements of enhanced hydrogen cyanide removal capability comprising a tobacco smoke filter element grade paper containing deposited substantially uniformly throughout said paper about 10 to 30% by weight of said paper of a water-soluble inorganic salt selected from the group consisting of sodium orthophosphite or potassium orthophosp-hite.

2. A creped cellulose tobacco smoke filter element prepared from paper containing deposited substantially uniformly over the surface of the paper therein a watersoluble inorganic weak basic salt selected from the group of salts consisting of sodium phosphite, potassium phosphite and lithium phosphite, in an amount of 1 to 30 percent based on the weight of the filter element, said element being capable of selectively removing a substantial amount of hydrogen cyanide from tobacco smoke.

3. A creped cellulose filter element according to claim 2 wherein the amount of the water soluble, inorganic, weak basic salt deposited substantially throughout the filter element is 2-10% based on the weight of the filter element.

(References on following page) 3 References Cited UNITED STATES PATENTS 760,772 11/1956 Great Britain.

2,172,946 9/1939 Sutter 131-265 I 2 76 13 10 1 5 Hiler 5 X 5 SAMUEL KOREN: Primary Exammel- 3,019,764 2/1962 Whitmore fit a1 131-266 D. J. DONOHUE, Assistant Examiner.

FOREIGN PATENTS 

